The present invention relates to a magnetoresistive effect element, magnetic head and a magnetic recording device, more specifically a magnetoresistive effect element having the CPP (Current Perpendicular to Plane) structure, in which the so-called spin valve film is used, and sensing current is flowed in the direction of the film thickness, and a magnetic head and a magnetic recording device using the magnetoresistive effect element.
A magnetoresistive effect element using a spin valve film includes 2 magnetic layers: one magnetic layer of which has the magnetization direction pinned by unidirectional anisotropic magnetic field with respect to the antiferromagnetic layer, etc., and the other magnetic layer of which has the magnetization direction easily changed by an external magnetic field. The property that the element resistance is changed by a relative angle of magnetization directions of these magnetic layers is utilized to detect a direction of the external magnetic field, based on the change of the element resistance.
As the conventional magnetoresistive effect element using the spin valve film is known a magnetoresistive effect element of the CIP (Current In-Plane) structure, in which sensing current is flowed in the direction of the plane of the spin valve film to detect the resistance change in the direction of the in-plane of the film.
On the other hand, as the magnetoresistive effect element of higher density and higher sensitivity is noted a magnetoresistive effect element of the CPP (Current Perpendicular to Plane) structure, in which sensing current is flowed in the direction of the film thickness of the spin valve film to detect the film thickness-wise resistance changes. The magnetoresistive effect element of the CPP structure has a characteristic that as the size is smaller, the element output increases and is prospective as a readout head of high sensitivity for used in high density magnetic recording device.
The Related arts are disclosed in, e.g., Reference 1 (Japanese published unexamined patent application No. 2001-325704), Reference 2 (Japanese published unexamined patent application No. Hei 07-287819), Reference 3 (Japanese published unexamined patent application No. 2000-216020), Reference 4 (Japanese published unexamined patent application No. 2003-317213), Reference 5 (Atsushi Tanaka et al., “Spin-Valve Heads in the Current-Perpendicular-to-Plane Mode for Ultrahigh-Density Recording”, IEEE Trans. Magn., Vol. 38, pp. 84-88, January 2002